Enhanced Oxygen Reduction on Hemin-Derived Fe–N Codoped Hierarchically Porous Carbon for Proton Exchange Membrane Fuel Cells

Although Pt-based catalysts demonstrate superior activity for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), their exorbitant cost and scarcity hinder large-scale commercialization. Therefore, it is crucial to develop inexpensive and high-performance ORR catalysts to replace Pt-based catalysts. Herein, Fe–N codoped hierarchically ordered porous carbon catalysts (Fe–N–HOPC) are fabricated using Hemin as a precursor and three-dimensionally ordered SiO₂ nanoparticles as a hard template. The incorporation of the hard template not only increases the specific surface area of the catalyst (124.8 m² g^–1) but also effectively prevents the formation of agglomerated Fe nanoparticles during the carbonization process. The as-fabricated Fe–N–HOPC exhibits excellent ORR catalytic activity under acidic conditions with a half-wave potential (E_1/2) of 0.74 V, high selectivity of nearly four-electron transfer, and appreciable stability. As a cathode catalyst in a PEMFC, a peak power density of 405.3 mW cm^–2 is delivered and a current density retention of 93.4% after 10 h of operation is achieved. This work provides a facile template-assisted method for designing and tuning of highly active Fe–N–C nonprecious metal catalysts toward practical ORR in PEMFC.